I first became interested in science when my brother told me there was a black hole under his bed (this was a ploy to prevent me from snooping there– this is how nerd children fight). Once I could read, I wanted to know if this could be possible; one should be skeptical of information provided by siblings. Frustratingly, none of the books I read discussed if an event horizon could be put under a bed. Pretty shoddy science. There was much discussion of micro-blackholes, with some description of their size. But what the heck was a nanometer? Bigger or smaller than a bed?
Even now, the scales of the universe boggle my mind. A human is so small. The diameter of the Earth (a small planet), is roughly 7 million times the height of a typical person. If you lined up every person in the state of Virginia head to toe, you would roughly approximate the Earth’s diameter. The diameter of the Sun is 100 times bigger (two orders of magnitude) than the Earth. If you lined up every person in the United States head to toe, you’d only get to half of the Sun’s diameter. The red giant Betelgeuse (the reddish star that is Orion’s left shoulder) is 700 times bigger than the sun.
The solar system is bigger yet–Neptune is 30 times as far from the Sun as Earth, at about 3200 times the radius of the Sun. It takes light 4 hours to reach Neptune. The Oort cloud, the farthest reach of our solar system and the hypothesized source of most comets, is a light year from the Sun.
Our solar system sits on one branch of the Milky Way, which is a galaxy 100,000 light years across (7×1011 times the diameter of the Sun–a meter is roughly 1012 times as big as a hydrogen atom). Our galaxy is 2.5 million light years from the nearest galaxy, Andromeda. Our galaxy is one of more than 50 galaxies in the Local Group. This piece of the universe is about 10 million light years in size. Wikipedia suggests there may be 100 billion galaxies in the universe. We have observed as far as 47 billion light years away, but the universe might be bigger (more intimidating statistics here).
And all of these things are slowly interacting. With all that, how could we not write science fiction?